1. Field of the Invention
The present invention relates generally to a method and apparatus for photographing a digital image, and more particularly, to a method and apparatus for photographing a panoramic image.
2. Description of the Related Art
Generally, a digital camera acquires an image of a scene formed in a focal distance of a lens. The acquired image exists within the range of the angle of view (in a general camera, about 30 to 50 degrees), which is narrower than the range of the viewing angle of a person looking at the same scene with their eyes, i.e., about 150 to 200 degrees. Thus, in order for a camera to produce a picture having an angle of view similar to or larger than that of the viewing angle of a person, several images are captured by changing a capturing angle and are then sequentially interconnected to create a single image. This is commonly referred to as a panoramic photographing scheme.
Conventionally, in a panorama photographing mode, a digital camera photographs several images such that they are continued in a horizontal or vertical direction, and stores the photographed images in a memory. The images stored in the memory are then provided to internal/external image processors to connect (or combine) them into a single image. To remove color differences and image discords occurring in boundaries of each of the images, the images are often captured to overlap each other at their boundaries. Therefore, when these images are processed into a single image, the overlapping portions are aligned, stitched, and/or blended, resulting in a single image in which the individual images are smoothly connected.
A key factor for panoramic image photographing is to photograph each of images in a manner that they are aligned as accurately as possible with each other. Often, a user performs photographing in a manual fashion by mounting a camera to an auxiliary apparatus such as a tripod, and the mounted camera is rotated for photographing of each image in panoramic image photographing. However, this panoramic image photographing task is somewhat complex and requires more proficiency in a user's manipulation of the camera, when compared to basic single picture photographing Consequently, there is a need for a more convenient manipulation and efficient panoramic photographing scheme.
Further, when an image is acquired by rotating a camera in a horizontal or vertical direction, the camera transforms a real image of a first object or a second object, which is in a three-dimensional (3D) form into a first image or a second image. When a panoramic image is implemented by combining these images, distortion occurs in perspective terms, such that overlapping portions of different images are difficult to estimate. As a result, a natural panoramic image cannot be formed. Therefore, there is a need for a panoramic photographing scheme, which generates a more accurate panoramic image by matching captured portions of the same region to each other in a plurality of images captured by the camera.